RESUMO
<p><b>OBJECTIVE</b>To investigate the changes of tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) in mice with cholestatic cirrhosis and their role in regulating the balance of liver stem cell differentiation.</p><p><b>METHODS</b>Balb/c mice were subjected to bile duct ligation (BDL), and serum biochemical parameters were measured and hepatic histopathology was observed using HE staining to evaluate the modeling of cholestatic cirrhosis. Immunohistochemistry and Western blotting were used to detect the changes of TNF-α and TGF-β in the mice after modeling. Mouse embryonic hepatic stem cells (HP14-19) were treated with different concentrations of TNF-α and TGF-β, and the cell differentiation was assessed using Western blotting, real-time PCR, and PAS staining.</p><p><b>RESULTS</b>The mice receiving BDL showed significantly increased blood biochemical parameters (P<0.05), and HE staining revealed obviously increased collagen fibers in the liver with significantly increased expressions of TNF-α and TGF-β (P<0.05). In HP14-19 cells, induction with TNF-α and TGF-β for 3 days did not cause significant changes in cell differentiation, but induction for 5 days resulted in significantly increases intensity of PAS staining in the cells. The cells induced with 20, 40, and 80 ng/mL TNF-α for 5 days exhibited a significantly stronger expression of cytokeratin 18 than cytokeratin 19 (P<0.05), while induction with 20, 40, and 80 ng/mL TGF-β produced opposite changes in cytokeratin 18 and cytokeratin 19 expressions. Further induction of the cells with TNF-α and TGF-β for 10 days, did not alter the expression patterns of cytokeratin 18 and cytokeratin 19 observed on day 5, but their protein expression levels and PAS staining intensity of the cells were enhanced and their mRNA expressions became lowered.</p><p><b>CONCLUSION</b>Common bile duct ligation can induce conditions simulating cholestatic cirrhosis in mice. TNF-α and TGF-β are elevated in cholestatic cirrhosis and play opposite roles in regulating the differentiation balance of liver stem cells: the former promotes the differentiation of liver stem cells into hepatocytes, while the latter promotes the cell differentiation into colangiocytes.</p>
RESUMO
<p><b>OBJECTIVE</b>To investigate the effects of different concentrations of all-trans retinoic acid (ATRA) on the maturation, differentiation and autophagy of Hepa1-6 cells.</p><p><b>MONTHOD</b>Hepa1-6 cells were treated with 0.1, 1, and 10 µmol/L ATRA, and the changes in the expressions of hepatic specific markers were detected using real-time PCR and Western blotting. Indocyanine green (ICG) and periodic acid-schiff (PAS) staining was used to assess the functional maturation of Hepa1-6 cells, and the cell-cell junction and autophagy were observed under transmission electron microscopy to determine the optimal concentration of ATRA for treatment. The expressions of autophagy-related markers in the cells were detected using Western blotting, and confocal microscopy was used to observe the autophagic flow in the cells transfected with ptfLC3 plasmid.</p><p><b>RESULTS</b>Compared with the control cells, the hepatocytes treated with ATRA showed a concentration-dependent decrease in AFP expression and increase in the expressions of ALB, CK18, TAT and ApoB. ICG and PAS staining revealed significantly increased number of positive cells after ATRA treatment. Following ATRA treatment, the cells exhibited obviously increased tight junctions, cytoskeleton and number of autophagosomes under transmission electron microscopy. ATRA treatment resulted in significantly increased the expressions of autophagy-related markers LC3-II, Beclin-1, RAB7 and P62 and also an increased ratio of LC3-II/LC3-I(P<0.05). Confocal microscopy revealed obviously increased green and red spots in the cells after ATRA treatment.</p><p><b>CONCLUSION</b>ATRA can induce the maturation and differentiation and enhance the level of autophagy in Hepa1-6 cells.</p>